Choice "B" is correct. The Statute of Frauds does not require that an agreement be signed by all parties, merely the party to be charged. The contract, however, generally is unenforceable against a party who did not sign.
Choice "d" is incorrect. The $500 threshold concerns sale of goods and not real estate.
Choice "c" is incorrect. There is no such rule. The contract could be made up of a series of writings, that when taken together reflect the material terms of the contract.
Choice "a" is incorrect. There is no such rule. The Statute of Frauds is concerned with whether certain contracts are evidenced by the party to be held liable under the contract and not with the fairness and adequacy of the price.